        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 20px;
        }

        .app {
            max-width: 600px;
            margin: 0 auto;
            background: white;
            border-radius: 16px;
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
            overflow: hidden;
        }

        .header {
            background: linear-gradient(135deg, #4CAF50, #45a049);
            color: white;
            padding: 24px;
            text-align: center;
        }

        .header h1 {
            font-size: 1.5rem;
            font-weight: 600;
        }

        .warning {
            background: #fff3cd;
            color: #856404;
            padding: 16px;
            margin: 0;
            border-bottom: 1px solid #ffeaa7;
        }

        .form-section {
            padding: 24px;
        }

        .form-group {
            margin-bottom: 20px;
        }

        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
            color: #2d3748;
        }

        .form-control {
            width: 100%;
            padding: 12px 16px;
            border: 2px solid #e2e8f0;
            border-radius: 8px;
            font-size: 14px;
            transition: all 0.3s;
        }

        .form-control:focus {
            outline: none;
            border-color: #4CAF50;
            box-shadow: 0 0 0 3px rgba(76, 175, 80, 0.1);
        }

        .btn {
            padding: 12px 24px;
            border: none;
            border-radius: 8px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s;
            font-size: 14px;
        }

        .btn:disabled {
            opacity: 0.6;
            cursor: not-allowed;
            transform: none !important;
        }

        .btn-primary {
            background: #4CAF50;
            color: white;
        }

        .btn-primary:hover:not(:disabled) {
            background: #45a049;
            transform: translateY(-1px);
        }

        .btn-danger {
            background: #f44336;
            color: white;
        }

        .btn-danger:hover:not(:disabled) {
            background: #da190b;
            transform: translateY(-1px);
        }

        .btn-success {
            background: #28a745;
            color: white;
        }

        .btn-success:hover:not(:disabled) {
            background: #218838;
            transform: translateY(-1px);
        }

        .btn-blue {
            background: #2b54e9;
            color: white;
        }

        .btn-blue:hover:not(:disabled) {
            background: #2b54e9;
            transform: translateY(-1px);
        }

        .btn-group {
            display: flex;
            gap: 12px;
            margin-top: 20px;
            flex-wrap: wrap;
            justify-content: space-between;
        }

        .status {
            padding: 16px;
            border-radius: 8px;
            margin: 16px 0;
            font-weight: 600;
        }

        .status.registered {
            background: #d4edda;
            color: #155724;
        }

        .status.unregistered {
            background: #f8d7da;
            color: #721c24;
        }

        .status.calling {
            background: #cce5ff;
            color: #004085;
        }

        .audio-section {

            background: #f8f9fa;
            padding: 24px;
            border-top: 1px solid #e9ecef;
        }

        .audio-controls {
            display: flex;
            align-items: center;
            gap: 16px;
            margin-top: 16px;
        }

        .mic-btn {
            width: 36px;
            height: 36px;
            border-radius: 50%;
            border: none;
            background: #2196F3;
            color: white;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s;
        }

        .mic-btn.muted {
            background: #9E9E9E;
            animation: pulse 1.5s infinite;
        }

        @keyframes pulse {
            0% {
                box-shadow: 0 0 0 0 rgba(158, 158, 158, 0.7);
            }

            70% {
                box-shadow: 0 0 0 12px rgba(158, 158, 158, 0);
            }

            100% {
                box-shadow: 0 0 0 0 rgba(158, 158, 158, 0);
            }
        }

        .volume-slider {
            flex: 1;
            margin: 0;
        }

        .mic-status {
            display: flex;
            align-items: center;
            gap: 8px;
            font-weight: 600;
        }

        .status-badge {
            padding: 4px 12px;
            border-radius: 12px;
            font-size: 0.8em;
        }

        .status-active {
            background: #d4edda;
            color: #155724;
        }

        .status-muted {
            background: #f8d7da;
            color: #721c24;
        }

        .log-section {
            background: #1a202c;
            color: #cbd5e0;
            padding: 16px;
            font-family: 'Courier New', monospace;
            font-size: 12px;
            max-height: 200px;
            overflow-y: auto;
        }

        .log-entry {
            margin-bottom: 4px;
        }

        .log-time {
            color: #63b3ed;
        }

        .log-error {
            color: #fc8181;
        }

        .audio-meter {
            height: 8px;
            background: #e2e8f0;
            border-radius: 4px;
            overflow: hidden;
            margin-top: 8px;
        }

        .audio-level {
            height: 100%;
            background: #4CAF50;
            width: 0%;
            transition: width 0.1s;
        }

        .audio-level.muted {
            background: #f44336;
        }